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[amibroker] Re: Convexity, Concavity and their use



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Dimitris;

Is it possible to use the peaks and troughs on an index (eg NDX) as 
Buy/Sell timing signals for the stocks in a watchlist?

I tried to change C1 = C into C1 = Foreign("NDX","C"); but that 
produced no output.

TIA
Keith



--- In amibroker@xxxxxxxxxxxxxxx, "Andrew" <a.perrin@xxxx> wrote:
> To measure how "deep" the concave/convex is you could insert these 
2 
> lines of code into DT's afl.  The greater the upward concave the 
> higher the value of positive value of "change", The greater the 
> downward concave the more negative the value of "change".
> 
> Change =((y-Ref(y,-t))/t) - ((y-Ref(y,-(t+1)))/(t+1))  ;
> Plot(Change,"Change",colorYellow,32770);
> 
> Andrew
> 
> --- In amibroker@xxxxxxxxxxxxxxx, "sidleysh" <steves@xxxx> wrote:
> > OK - I will try and be more articulate.
> > 
> > The code you generously developed identified concave and convex 
> > shapes in the chart, after some initial smoothing. This indicates 
> > areas where the chart was accelarating or decelerating in either 
> > an 'up' direction or a'down' direction. You identified these as 
> > bullstart, bearstart, etc.
> > 
> > I optmizied on both your K paraneter (for smoothing) and T 
> parameter 
> > (for lookback period) and was able to get nice resutls for 
> indivdual 
> > stocks, but could not find a robust set of paramters for a basket 
> (in 
> > this case the NDX100).
> > 
> > This led to a suggestion for 2 possible improvements to the code:
> > 
> > 1) A way to identify only 'deep' concaves and convexes - which 
> would 
> > signal fast acceleration/deceleration, which, presumably would 
> signal 
> > the start of a short trend. For 'shallow' concaves and convexes, 
> the 
> > strategy would be to hold position.
> > 2) A more adaptive smoothing algorithm
> > 
> > 
> > Cheers,
> > 
> > Steve
> > 
> > 
> > --- In amibroker@xxxxxxxxxxxxxxx, "DIMITRIS TSOKAKIS" 
> <TSOKAKIS@xxxx> 
> > wrote:
> > > If you have the time, it would be better to give more specific 
> > > descriptions/codes. This would help the [more than 1000] 
readers 
> to 
> > > understand better your text ["optimize", "delta" etc]
> > > This would also help the progress of this [hopefully 
> interesting] 
> > > thread.
> > > Dimitris Tsokakis
> > > --- In amibroker@xxxxxxxxxxxxxxx, "sidleysh" <steves@xxxx> 
wrote:
> > > > DT - thanks, good stuff. Obviously the smoothing algorithm 
> causes 
> > a 
> > > > lag in signal, so I am finding good results when I optimize, 
> but 
> > I 
> > > > fear I am curve fitting.  (I cannot find a set of coefficents 
> for 
> > K 
> > > > and T that work reasonably over the whole market). 
> > > > 
> > > > This could be vastly improved by only trading on 'serious' 
> > > covexities 
> > > > and concavities, and staying out for the shallow ones. The 
> > serious 
> > > > ones could be defined as when today delta is greater than 2* 
> > > > yesterday's delta, which is greater than 2* the previous 
day's 
> > > delta 
> > > > (or some such). You then stay in the trade (long) until it 
> starts 
> > > to 
> > > > descend. 
> > > > 
> > > > --- In amibroker@xxxxxxxxxxxxxxx, "Dimitris Tsokakis" 
> > > <TSOKAKIS@xxxx> 
> > > > wrote:
> > > > > An ideal sinusoidal has 4 phases:
> > > > > 
> > > > > Convex AND Ascending;// colorDarkGreen
> > > > > Concave AND Ascending;// colorTurquoise
> > > > > Concave AND Descending;// colorDarkRed
> > > > > Convex AND Descending;// colorPink
> > > > > The IB code illustrates the example 
> > > > > 
> > > > > // The 4 phases of an ideal sinusoidal
> > > > > freq = 1;
> > > > > y=sin( Cum( freq/10 ) );
> > > > > t=1;
> > > > > Convex=(y-Ref(y,-t))/t>=(y-Ref(y,-(t+1)))/(t+1);
> > > > > Concave=NOT(Convex);
> > > > > Ascending=y>=Ref(y,-1);
> > > > > Descending=NOT(ascending);
> > > > > Bullstart=Convex AND Ascending;
> > > > > Bullend=Concave AND ascending;
> > > > > Bearstart=Concave AND Descending;
> > > > > Bearend=Convex AND Descending;
> > > > > Color=IIf(Bullstart,colorDarkGreen,IIf
> > (Bullend,colorTurquoise,IIf
> > > > (Bearstart,colorDarkRed,colorPink)));
> > > > > Plot(y,"",Color,8);
> > > > > 
> > > > > [see sin.gif]
> > > > > We shall use a smoothing procedure [IIR2 filter] as close 
to 
> > the 
> > > > sinusoidal as possible. [see IIR2.gif]
> > > > > Of course the trend characteristics do not give the [-1, 
+1] 
> > > > oscillation, but the convexity/concavity are still detectable.
> > > > > The superimpose of actual price candles gives a more 
> > descriptive 
> > > > picture of the 4 phases.
> > > > > [see 4phases.gif]
> > > > > The full code is
> > > > > 
> > > > > // The 4 phases of a stock graph
> > > > > // A. Smothing procedure
> > > > > function IIR2( input, f0, f1, f2 )
> > > > > {
> > > > > result[ 0 ] = input[ 0 ];result[ 1 ] = input[ 1 ]; 
> > > > > for( i = 2; i < BarCount; i++ )
> > > > > {
> > > > > result[ i ] = f0 * input[ i ] + f1 * result[ i - 1 ] + f2 * 
> > result
> > > [ 
> > > > i - 2 ]; 
> > > > > }
> > > > > return result;
> > > > > }
> > > > > C1=C;
> > > > > k=0.3;
> > > > > RD=IIR2( C1, 0.3, 1.2+K, -0.5-K);
> > > > > // B. Convexity definition
> > > > > y=RD;
> > > > > t=1;
> > > > > Convex=(y-Ref(y,-t))/t>=(y-Ref(y,-(t+1)))/(t+1);
> > > > > Concave=NOT(Convex);
> > > > > Ascending=y>=Ref(y,-1);
> > > > > Descending=NOT(ascending);
> > > > > // C. Trend phases
> > > > > Bullstart=Convex AND Ascending;// from A to B
> > > > > Bullend=Concave AND ascending;// from B to C
> > > > > Bearstart=Concave AND Descending;// from C to D
> > > > > Bearend=Convex AND Descending;// from D to E
> > > > > // D. Application
> > > > > Color=IIf(Bullstart,colorDarkGreen,IIf
> > (Bullend,colorTurquoise,IIf
> > > > (Bearstart,colorDarkRed,colorPink)));
> > > > > Plot(y,"",Color,8+styleThick);
> > > > > Plot(C,"",47,64);GraphXSpace=5;


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